Square D 8501HO40 Relays

Square D 8501HO40 is a rugged NEMA control relay in the Square D 8501 HO40 family, built for industrial control and automation tasks where long life and reliability matter. This 8501HO40 variant belongs to Schneider Electric’s 8501 Type HO line and uses a 120 V AC coil (Series D), designed to drive clean, isolated switching in control circuits. The 8501 family is engineered around a modular, replaceable contact cartridge concept, offering long service life and easier maintenance in demanding environments, with the 8501 lineup commonly used in machine tools and industrial automation panels. Applications include machine tools, distribution panels, bottling and packaging lines, and other industrial control systems that require robust electromechanical relays; the HO40 family is part of Square D’s broader NEMA relay ecosystem, compatible with a wide range of accessories and mounting options to fit different control architectures.